Muscular System Flashcards
What are the three types of muscle tissue?
Skeletal, Cardiac, Smooth
How do the different muscle tissues differ?
Microscopic anatomy, location and control by the nervous and endocrine system
What is the basic physiological property of muscle tissue?
Contractility: the ability to contract and shorten
4 physiological properties of muscle tissue
Excitability (irritability)
Extensibility
Elasticity
Contractility
Excitability (irritability)
The capacity to receive and respond to a stimulus
Extensibility
The ability to be stretched
Elasticity
The ability to return to original shape after being stretched or contracted
What type of muscle is attached primarily to bones and moves parts of the skeleton?
Skeletal
Skeletal muscle is striated
True
Striations
Produced by a characteristic arrangement of contractile proteins, myosin and actin
Skeletal muscle is an involuntary muscle
False
It can be made to contract and relax by conscious control
How are muscles attached to bones?
Tendons
The eternal sphincter of the bladder and diaphragm cause movement of the skeleton
False
And they do not attach to bone
What is a fascicles?
Bundles of muscle fibers in skeletal muscle
Epimysium
Enclosed fascicles
Fascicles are separated by connective tissue fibers of the…..
Perimysium
Muscles fibers in fascicles are surrounded by the
Endomysium
Satellite cells lie between the __________ and _______
Endomysium and muscle fibers
What is the function of satellite cells?
Repair damaged muscle tissue
Epimsium
Sheath of connective tissue surrounding the muscle
Fascicle
Bundle or cluster of muscle fibers
Perimysium
Sheath of connective tissue surrounding each fascicle
Muscle fiber
Muscle cell
Sarcolemma
Plasma membrane of muscle cell
Myofibiril
Threadlike structure running longitudinally through a muscle fiber
Myosin
Thick filaments
Actin (troponin and tropomyosin)
Thin filaments
Myofilaments are arranged in
Sarcomeres
What is the basic contractile unit of striated muscle fibers?
Sarcomeres
Cardiac muscle is striated
True
But it looks very different from skeletal muscle
Where is cardiac muscle found?
In the heart
Myocardial cells are long/short and branched/unbranched
Short,branched
Cardiac muscle is intimately interconnected to form continuous fabric
True
Intercalated discs are found in all types of muscle
False
What are intercalated disks
Special areas of contact between adjacent cardiac muscle cells
Gap junctions
Found in intercalated discs and couple myocardial cells together mechanically and electrically
Both skeletal muscle and cardiac muscle can produce a graded contraction by varying the amount of cells stimulated to contract
False
Skeletal muscles can cardiac muscles cannot
Why does cardiac muscle act as a whole?
All cells in the myocardium are electronically joined, by gap junctions. Stimulation of one cells results in the stimulation it all other cells and the whole heart contracts
What is the driving force behind movement?
Muscle tissue
The heart contracts to its fullest extent each time because all of its cells contribute to contraction
True
How can the ability of myocardial cell contraction be increased?
Sympathetic systems and stretching of the heart chambers
What are the 2 chambers of the heart?
Atria and ventricles
Both skeletal and cardiac muscles require external stimulation by somatic motor nerves before they can produce action potentials and contract
False.
Cardiac muscle able to produce action potentials automatically
Pacemaker
Group of cells that cardiac action potentials originate
Transverse tubules
Small cylindrical invaginations of sarcolemma of striated muscle fiber hat conduct muscle croon potentials towards the center of the muscle fiber
Skeletal and cardiac muscle
Smooth muscle fibers are short/long, __________shaped, and slender/thick
Short, spindle, slender
Smooth muscle fibers contain more than one nucleus
False
1 nucleus, located near the center of the fiber at its widest point
Troponin is present in smooth muscle fibers.
False
Actin, myosin and tropomyosin are present
Smooth muscle is not striated
True
Actin filaments in smooth muscle are attached to __________that are distributed throughout the __________in a network of intermediate filaments
Dense bodies, sarcoplasm
Smooth muscles contract very quickly
False
2 types of smooth muscle
Single unit and multiunit
Single unit smooth muscle
Most common
Found in the walls of tubes and hollow organs (blood vessels, bladder)
Smooth muscle and cardiac muscle contracts as a whole due to what
Cells are connected to one another by gap junctions
Smooth muscles have pacemaker cells
True
In single unit cells
Multiunit smooth muscles consist of individual fibers, each with its own motor neuron terminals
True
All smooth muscle fibers cause contraction of all adjacent fibers.
False
Single unit cells contract all other cells
Multiunit cells only contract within that fiber
Where are multiunit smooth muscle fibers found?
Walls of large arteries, bronchioles, radial and circular muscles of the iris that adjust pupil diameter and in the ciliary bodies that adjust focus of the lenses of the eye
Sarcomeres are present in smooth muscle fibers
False